I intend to remove the prefixed CSS property
-moz-force-broken-image-icon in bug 1348208 , and add a new
"browser.display.force_show_broken_image_placeholder" pref to replace
This property is for forcing showing the image placeholder for broken
images. It is initially added for making Gecko's behavior align with IE.
However, as far as I can see, no other modern browser has such behavior
(at least by default) nowadays. None of Chrome, Safari, and Edge shows
the placeholder icon for broken images.
Since this only applies to broken images, I don't expect it to break
There are some non-trivial number of mentions to this property according
to search result, but it seems to me most usecases are that authors want
to find broken images easier, and thus most of its usages seem to be in
user style rather than author style. It is a clear indication that it
should be a pref rather than a CSS property.
BTW, I guess devtools may want to add some support around the new pref
to help authors find broken images.